/Engine/Source/Editor/UnrealEd/Classes/Editor/EditorEngine.h
Optimize a level's Bsp, eliminating T-joints where possible, and building side links. This does not always do a 100% perfect job, mainly due to imperfect levels, however it should never fail or return incorrect results.
virtual void bspOptGeom ( [UModel](API\Runtime\Engine\UModel) * Model )